Yes, the serial number printed or heat stamped into the hub. How to interpret the number depends on who manufactured the disc.
For Moser Baer & Prodisc the serial number starts with a group of (usually) 4 numerals, such as 4123. The first numeral denotes the year - in this case 2014, or on old discs 2004. The rest are which day of the year the disc was made - in this case the 123rd day, which is 3rd May (or 2nd May in leap years).
For CMC Magnetics the code is more complicated and is decoded as shown in the image below.
I don’t know of a method to identify the manufacturing date of discs made by Falcon Media (FTI) or Verbatim’s own factory in Singapore. But if there is a method it must involve the hub code. The other number you can see on the underside of the disc on the inner edge of the recording are is the stamper code. Stampers are very expensive and have a long working life, so are changed infrequently.
[B][U]Deciphering CMC Magnetics hub codes[/U][/B]